[GR-20761] initialize bytes and bytearrays from foreign array like objects (i.e., host arrays: int[], short[], etc)

PullRequest: graalpython/789

Author: cosminbasca

graalpython/com.oracle.graal.python.test/src/com/oracle/graal/python/test/interop/JavaInteropTest.java

@@ -182,6 +182,18 @@ public void javaArraySet() {
             assertPrints("42\n", source);
         }
 
+        @Test
+        public void javaArrayBytes() {
+            String source = "import java\n" +
+                            "array = java.type(\"short[]\")(4)\n" +
+                            "array[0] = 1\n" +
+                            "array[1] = 2\n" +
+                            "array[2] = 3\n" +
+                            "array[3] = 4\n" +
+                            "print(bytes(array))\n\n";
+            assertPrints("b'\\x01\\x02\\x03\\x04'\n", source);
+        }
+
         @Test
         public void testPassingFloats() throws UnsupportedEncodingException {
             String source = "import polyglot\n" +

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/util/CastToByteNode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -87,6 +87,20 @@ protected byte doByte(byte value) {
         return value;
     }
 
+    @Specialization(rewriteOn = ArithmeticException.class)
+    protected byte doShort(short value) {
+        return PInt.byteValueExact(value);
+    }
+
+    @Specialization(replaces = "doShort")
+    protected byte doShortOvf(short value) {
+        try {
+            return PInt.byteValueExact(value);
+        } catch (ArithmeticException e) {
+            return handleRangeError(value);
+        }
+    }
+
     @Specialization(rewriteOn = ArithmeticException.class)
     protected byte doInt(int value) {
         return PInt.byteValueExact(value);